As your average webmaster I can say for my self that the skin does not atract me particularly, it's more the reputation of the sponser that atracts.
Of course it is agood idea just for branding, bt for me and I think most webmasters that do this for a living I doubt that it is a determing factor.
Btw. why don't the big guys brake into the Japanese market?
Huge market, and they don't charge back, I know of a sponser that has never gone over 0.2%